Bottles, or other containers, are often packaged in cardboard packing cases of the type having interconnected top flaps at diagonally opposite corners of the case to hold the top flaps close to the sides of the case during case loading.
The top flaps of the loaded cases must then be closed, and this requires that these tabs be slit before the top flaps can be moved away from the sides of the case. Prior art patents related to such tab slitting apparatus generally teach that the case must be rotated 90 degree between the slitting of the rear tab and the front tab, at least where the slitting knife is stationary, and the case moves past the fixed knife as shown for example in U.S. Pat. Nos. 3,373,543, 3,533,214, 3,559,368, 3,726,061, and 3,733,772. U.S. Pat. No. 3,387,522 illustrates a straight line path for such a case in a tab slitter, but this patent requires that at least one knife be movable rather than stationary.
The chief aim of the present invention is to provide an apparatus for slitting the diagonally opposite top flap connecting tabs of a packing case wherein the case moves straight through the apparatus past the fixed knives, without necessity for rotating the case on a vertical axis to slit the leading tab. Other advantages to the present invention will be apparent, particularly in respect to the infeed means for spacing the cases to be slit, and the top flap folding means provided downstream of the these fixed, tab slitting, knives.